Gas mask



F. HOFSTCTTER March 16, 1937.

' GAS MASK Filed se t. 1, 1936 Patented Mar. 16, 1937 UNITED STATES PATENT IIOFFICIE' m Hardest: swimmer;

Application September 1, 1936, Serial No."98,936

.In Germany September 9, 1935" v cla ms. (c1..,1 2s 141) This invention relates to gas-masks.

Various forms of gas-masks have already been proposed and in order that a gas-mask should be suitable for general use' among the civilian popu- 5 lation it is desirable for it to be light in weight andcheap to manufacture.

4 In the gas-mask according to the present invention these and other desiderata are realized in that a foundationof fabric, provided with eyeholes is coated with a colourless lacquer forming a. continuous airtight skin extending across and forming a'transparent closure for the eyeholes.

This and other features of the invention will V now be desbribedwith reference to the accompanying drawing, i which one embodiment is shown byway of example. Fig. 1 is a side View of a complete gas-mask.

Fig. 2 is a front view of the mask with the filter element removed. Fig. 3 is a horizontal section through the mask.

,. Fig. 4 is a largerscale section through the eyeholesof a modified gas-mask.

The fabric foundation I, which should be.substantially inextensible, is provided with eyeholesor windows la.\which extend over 'aconsiderable portion of the face of the wearer. ,This not only gives a very wide angle of .vision but also enables the wearer to be recognized readily. The mouthpiece. 2 into which the filter element '3 can be .screwed is provided in the foundation. The customary harness or strap system for securing the mask inposition is also associatedwith'the foundation. Thefoundation is coated with cellulose lapqueri which at the eyeholes la forms a self-supporting flexible closure foil. The periphcry of the mask is folded inwardly and the lacquer coating extends continuously onto the inside of the .;fold. if. In this way .the lacquer coating forms an entirely jointless surface extendingover 40 the entire mask foundation except for the socket where the filter element is, attached; Due. to its flembility, smoothness and high power of adhesion,the lacquer coating'provides a reliable seal where it contacts with the skin of the wearer.- The fabric foundation is permeated by the cellulose lacquer during the application of the. coating so that the latter is firmly and reliably attached without auxiliary securing means. v

If it is regarded as necessary to provide sealing strips of soft leather on the inside of the fold If,

' these strips may be secured in position by placing them on the lacquer coating before it has dried.

l Acoatirrg of lacquer may be applied to both sides of the mask foundation instead of to one out going beyond the' scop of my or the mask may-be dispensed with so that the sk will better adapt itself to the shape of the face of the wearer. The transparent lacquer coating renders unnecessary the rubber material hitherto customarily used,- eliminates the'inserr tion .of separate windows and also makes it possible to dispense with the sealing strips of soft leather or the like which previously have been regarded as necessary for a tight closure between the periphery of the mask and the wearer.

Moreparticularly when a very light fabric is .employed for the foundation and a softer lacquer coating is provided, the mouthpiece may be disposed at the intersection of auxiliary reinforcing strips of fabric, metal or the like which extend to the points of attachment of the strap system.

Due to its light weight, the wide field of vision, fcheapness of'manufacture and the possibility of repairing the lacquer coating more readily than rubber, the gas-mask as described and illustrated is particularly suitable for use by the civilian population while following their occupations.

The gas-mask according to the invention may, for example, be produced in the following way; A suitable qua'ntityof the colourless liquid lacquer, varying with its consistency, is'caused to thicken on the polished surface of a horizontally disposed glass plate of appropriate dimension. The quantity of lacquer is so chosen that the flex ibl'e transparent coating has the desired thick-v o ness. Cellulose or. acetyl-cellulose, with a suitable addition of softener, is employed aslacquer. The'streng th of the lacquercoating is deters mined by its thickness. The foundation, pre-f viously cut to the desired configuration, is pressed onto the lacquer layer until the lacquer penetrates through the fabric and runs together to formathin coating-on the other side. A further layer of lacquer may be applied to theinside of the fabric to enhance the mechanical strength as indicated in Fig. 4, at 5'I' When the lacquer is dry, the whole is removed from the glass plate and made up intothe mask.

I do not limit. myself to the particular size, shape, number or arrangement of partsas shown 45 and described, all of which may be varied withinvention as" shown, described and claimed.

What I claim is? 5 1. In a gas-mask, a-foundation of fabric, eye- 4 holes provided in said foundation, and an airtight, transparent, pliablefoil covering said foundation throughout its areal extent and forming a selfsupporting window across said eyeholes as an integral part of said 1011,101- constituting a 101mless gas-mask together with said foundation.

2. In a gas-mask, a foundation of fabric, eyeholes provided in said foundation, an airtight, transparent, pliable foil covering said foundation throughout its areal extent and forming a selfsuppmfting window across-said eyeholes as an integral part of said foil, for constituting ajointless gas-mask together with said foundation, and

an inturned marginal strip on said foundation providing a sealing Joint with the shunt the Q wearerby-bearing engagement therewith.

3. In a gas-mask, a foundation of fabric, eyehoies provided in said foundation, and an airtight, transparent, pliable coating of lacquerpenetrating through said foundation through ut its.

areal extent from theputside thereof and forming a self-supporting window across said eyeaoholesasanintegraipartofsaidcoatinmfor constituting a Jointiessl gas-mask together with,

said foundation.

4. In a gas-mask, a foundation of fabric, eyeholes provided in said foundation, an airtight,

an integral part of, said coating, for constituting a jointless gas-mask together with said foundation, an inturned marginal strip on said foundation providing a sealing joint with the skin of the wearer by bearing engagement'therewith, and V a second coating applied to the inner side of said mask. v

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